There is a newish WikiTree'er who has been making "enthusiastic" mistakes almost since he started. He's very nice and easy to work with. However, the severity of the errors seems to be increasing.
For example, there is a family that named their three sons the exact same name, calling them El Primero, El Segundo, and El Tercero (First, Second, and Third). There is a Research Note that clearly explains the situation, even listing their individual wives. Two of the profiles were orphans. The Newby Guy adopted those two and merged them. He tried to set up a merge with the third brother but it was rejected by the PM. I recreated the profile for the oldest son and fixed all the family relationships that were changed by the merge.
I've worked with him on several other issues, such as attaching new spouses or children without sources or working on pre-1600 profiles, explaining the reasons. It looks like a few others have done the same. I can continue this but at some point I think a mentor should work with him.